Safety of heat generated by endoscope light sources in simulated transcanal endoscopic ear surgery

Thermal variation in human temporal bone using rigid endoscope

OBJECTIVE

Compare thermal variation in the region of the External Acoustic Canal (EAC) and the Round Window (RW) using different rigid endoscopes and light sources in human temporal bones.

METHOD

This is an analytical experimental study using human temporal bones. Thermal variation was assessed during ten minutes, using a thermometer in the region of the EAC and the RW of two temporal bones, right and left. We used three different endoscopes (0° 4-mm, 0° 3-mm and 30° 4-mm) and five intensity/type light source (Halogen 100%, LED 50%, LED 100%, Xenon 50% and Xenon 100% with the same endoscope light fiber.

RESULTS

We found temperature elevations in the EAC and RW in all measurements. Larger caliber endoscopes (4-mm) and light sources at 100% intensity generated higher temperatures, slightly higher in halogen and xenon. The 30° endoscopes tended to put more heat on structures, with little difference in most measurements. We identified greater temperature variations in the EAC of the right and left temporal bones compared to the RW overall. The highest temperature acquired in the present study was in the EAC of the temporal bone with a 4-mm and 30° endoscope, using xenon light source (intensity of 100%), with an increase of 4.51 °C.

CONCLUSION

The type of endoscope and light source can influence the thermal variation and the risk of tissue injury during endoscopic ear surgery. Larger endoscopes with xenon and halogen light sources at maximum intensity generate more heat.

LEVEL OF EVIDENCE: 5

Temperature and luminosity outputs of endoscopes used in transcanal endoscopic ear surgery: an experimental study

OBJECTIVE

To establish the relationship between endoscope temperatures and luminosity with a variety of light source types, endoscope ages, endoscope sizes, angles and operative distance in transcanal endoscopic ear surgery.

METHODS

Transcanal endoscopic ear surgery was simulated in an operating theatre using 7 mm plastic suction tubing coated in insulating tape. An ATP ET-959 thermometer was used to record temperatures, and a Trotec BF06 lux meter was used to measure luminosity. Luminosity and temperature recordings were taken at 0 mm and 5 mm from the endoscope tip.

RESULTS

Thermal energy transfer from operating endoscopes is greatest when: the light intensity is high, there is a light-emitting diode light source and the endoscope is touching the surface. Additionally, larger-diameter endoscopes, angled endoscopes and new endoscopes generated greater heat.

CONCLUSION

It is recommended that operative light intensity is maintained at the lowest level possible, and that the surgeon avoids contact between patient tissues and the endoscope tip.

Preclinical Assessment of Tissue Effects by Gastrointestinal Endoscope Tip Temperature

Background

Endoscope tips are heated by their electrical and illuminating components. During the procedure, they might get in close or even direct contact with intestinal tissues.

Objective

To assess endoscope tip and tissue temperature as well as histopathologic changes of gastrointestinal (GI) tissues when exposed to the heated tip of GI endoscopes.

Methods

The endoscope tip temperatures of four GI endoscopes were measured for 30 minutes in a temperature-controlled chamber. The temperature of ex vivo porcine GI tissues was measured for 5-, 15-, and 120-minute exposure to endoscope tips within a climate chamber to control environmental factors (simulation of fever as worst-case). Exposed tissues were histopathologically examined afterward. Control samples included untreated mucosa, tissue samples exposed to endoscope tips for 120 minutes, as well as tissue samples thermally coagulated with a bipolar high-frequency probe.

Results

Actual endoscope tip temperatures of 59 to 86°C, dependent on the endoscope type, were measured. After 10 to 15 minutes, the maximum temperatures were reached. Maximum tissue temperatures of 44 to 46°C for 5 and 15 minutes, as well as up to 50°C for 120 minutes, were recorded dependent on tissue and endoscope type. No direct heat-induced histopathologic tissue alterations were observed in the 5- and 15-minute samples.

Conclusions

Both clinically relevant and a worst-case control were tested. Even though elevated temperatures were recorded, no heat-related tissue alterations were detected. This overall supports the safety profile of GI endoscopy; however, the study findings are limited by the ex vivo setting (no metabolic tissue alterations accessible, no blood flow) and small sample number.

Endoscopic vs. microscopic stapes surgery: An anatomical feasibility study

Objectives

To investigate the feasibility of the endoscopic approach vs. microscopic approach during stapes surgery, focusing on the visualization of the important anatomical structures of the middle ear, the volume of the resected scutum and chorda tympani (CT) injury.

Methods

Fresh frozen human cadaveric heads underwent two stapes surgeries using an operating microscope on one ear and an endoscope on the other ear. The surgeon documented the visualization of critical landmarks, as well as exposure and injury of the CT. The volume of resected scutum was evaluated using cone beam computed tomography scanning and three-dimensional imaging.

Results

We performed endoscopic stapes surgery in 10 ears and microscopic stapes surgery in 11 ears. A stapes prosthesis was placed in all ears. The volume of bony scutum resection was significantly lower in the endoscopic group (median = 2.20 mm³, IQR = 4.17) than in the microscopic group (median 13.25 mm³, IQR = 8.71). No scutum was removed in two endoscopic ears, while scutum was removed in all microscopic ears. The endoscopic and microscopic group had similar CT injury.

Conclusions

This study showed that the endoscopic stapes surgery procedure is feasible and might be less invasive than microscopic stapes surgery. Future clinical prospective and functional studies will be needed to support our findings.

“Hot” vs “Cold” endoscopic stapes surgery: a matched case–control study

Purpose

To compare hearing results and complication rates between two groups of patients operated on by endoscopic stapes surgery (ESS) for otosclerosis, either with CO2 fiber laser or microdrill.

Methods

A case–control study was performed. All consecutive cases of CO2 fiber laser ESS operated at a single center during the period 2017–2020 (case group) were matched to a control group of patients operated by traditional technique, according to year of surgery, preoperative mean air–bone gap, sex and age. Audiological data from preoperative and postoperative examinations and complication rates were compared.

Results

46 cases were included. Mean operative time was significantly longer in the laser cohort (65 min) than in the drill one (45 min) (p = 0.003). Similar results were found in the two groups regarding the mean postoperative BC-PTA. The high-frequency bone conduction resulted significantly higher in the laser group (p = 0.002), suggesting an overclosure effect in the laser group. Consistently, a significant improvement of the BC-PTA threshold at 2000 Hz postoperatively was found in the laser group (p = 0.034). The postoperative AC-PTA significantly improved in both groups at all frequencies (p < 0.05), except for the AC threshold at 8 kHz. Similar rates of complications were found in the two groups.

Conclusion

This study is the first to compare hearing results and complications between CO2 fiber laser and microdrill in ESS. Our results demonstrated similar functional outcomes between the two groups, confirming ESS as safe and effective, regardless of the technique used.

Outcomes and learning curve of endoscopic tympanoplasty: A retrospective analysis of 376 patients

Objective

This study aimed to evaluate the procedural outcomes and learning curve of type I endoscopic tympanoplasty (ET) performed by a single surgeon.

Methods

This was a retrospective study of 376 patients who underwent type I ET performed by a single surgeon over 7 years. We evaluated the pre/post air-bone gap (ABG), time required for surgery, changes in pain after surgery, success, and failure rate of type I ET.

Results

Hearing results indicated an ABG of approximately 17.8 dB before surgery but decreased significantly to 9.8 dB at 6 months after surgery. The time required for the operation gradually decreased. In particular, the time required for the procedure was 67.6 min in the first year and decreased to 31.5 minutes in the fifth year, a drastic reduction. The graft failure rate up to 6 months after surgery was 13.0% and was the same for both primary and revision surgeries. Graft failure was significantly greater with increasing size of the preoperative tympanic perforation. The success rate varied depending on graft material, and the group with only acellular allogenic dermal matrix showed the lowest success rate. Postoperative pain significantly decreased from 2.01 immediately after surgery to 0.78 points the next day, and there were no severe complications during surgery.

Conclusions

ET produces superior cosmetic results with minimal pain and is associated with stable hearing improvement and high success rate. The operation time decreased with surgeon experience and continued to decrease until the fifth and final year of this analysis.

Level of Evidence

4.

Taste impairment after endoscopic stapes surgery: Do anatomic variability of chorda tympani and surgical technique matter? : Post-operative dysgeusia after EStS

PURPOSE

To investigate how the anatomical configuration of the oval window region (OWR) influences the management of the chorda tympani (ChT) and the curetting of adjacent bony structures, in a setting of patients undergoing endoscopic stapes surgery (EStS); to assess the incidence of early and late post-operative dysgeusia and to identify anatomical and surgical factors influencing taste function after EStS.

METHODS

Surgical video recordings of 48 patients undergoing EStS for otosclerosis between January 2019 and July 2020 were retrospectively revised, to classify the anatomical variability of selected middle ear structures and the management strategies for the ChT. Clinical records of included patients were reviewed for subjective early and late post-operative taste impairment using a 5-point Likert-scale.

RESULTS

The most common configuration of the OWR was type III. The extension of the bony curettage resulted inversely proportional to the exposure of the OWR. The long-term rate of preserved post-operative taste function was 85%. Displacement of the ChT was necessary in 43/48 cases (90%), mostly medially (36/48, 75%).

CONCLUSION

Bone curetting during EStS does not correlate with post-operative taste impairment. Despite 100% ChT preservation rate, dysgeusia may occur in a minority of patients, with no apparent relationship to anatomical variability or intraoperative management of the ChT. The use of CO₂ laser could have a role in increasing the risk of post-operative dysgeusia after EStS.

[Endoscopically guided reconstruction of the ossicular chain-an introduction]

The term "endoscopic ossiculoplasty" refers to surgical methods with the intention to reconstruct the ossicular chain using endoscopic vision. Apart from malformations and injuries, inflammatory processes cause the majority of indications for ossicular reconstruction. This article offers a commented overview of current literature and preliminary personal experience.

Limits in endoscopic ear surgery

BACKGROUND

In recent decades, endoscopic ear surgery (EES) has been rapidly evolving, expanding its boundaries from the middle ear to the lateral skull base. Nonetheless, the advantages of the endoscopic technique are associated with a number of intrinsic limitations.

METHODS AND OBJECTIVE

A narrative review was conducted to investigate the current limits of EES, analyzing the different otologic and skull base surgery procedures.

RESULTS

Limitations of EES can be divided into general and procedure-related. General limitations have been extensively described in the literature and are related to the bidimensional image provided by the endoscope, as well as the one-handed surgical technique and its implications in the management of bleeding. Procedure-related limits are continuously evolving and are also discussed in the present review.

CONCLUSION

Although endoscope use is intrinsically associated with general limitations, these have been systematically overcome by the refinement of the surgical technique as a consequence of the increasing surgical experience gained over the last 20 years. The main limits of EES are currently associated with specific procedure- and disease-related situations. This review describes the general limitations and their management, as well as the current limits in the endoscopic management of various otologic diseases, from the external ear to the lateral skull base.

Thermal Safety of Endoscopic Usage in Robot-Assisted Middle Ear Surgery: An Experimental Study

Objectives: The widespread application of endoscopic ear surgery (EES), performed through the external auditory canal, has revealed the limitations of the one-handed technique. The RobOtol® (Collin ORL, Bagneux, France) otological robotic system has been introduced to enable two-handed procedures; however, the thermal properties of dedicated endoscopes, which are usually used in neurosurgery, called "neuro-endoscopes," have not yet been clarified for the robotic systems. In this study, we aimed to profile the thermal characteristics of two dedicated neuro-endoscopes, as compared to endoscopes used routinely in manual EES, called "oto-endoscopes," and defined by a smaller diameter and shorter length, and to discuss the safe application of robotic assistance in EES. Methods: Two neuro-endoscopes (3.3 mm, 25 cm, 0°/30°) were studied using two routine light sources (LED/xenon), and two routine oto-endoscopes (3 mm, 14 cm, 0°/30°) were initially measured to provide a comprehensive comparison. Light intensities and temperatures were measured at different power settings. The thermal distributions were measured in an open environment and a human temporal bone model of EES. The cooling measures were also studied. Results: Light intensity was correlated with stabilized tip temperatures (P < 0.01, R ² = 0.8719). Under 100% xenon power, the stabilized temperatures at the tips of 0°, 30° neuro-endoscopes, and 0°, 30° oto-endoscopes were 96.1, 60.1, 67.8, and 56.4°C, respectively. With 100% LED power, the temperatures decreased by about 10°C, respectively. For the 0° neuro-endoscope, the illuminated area far away 1cm from the tip was below 37°C when using more than 50% both power, while this distance for 30° neuro-endoscope was 0.5 cm. In the EES temporal bone model, the round window area could reach 59.3°C with the 0° neuro-endoscope under 100% xenon power. Suction resulted in a ~1-2°C temperature drop, while a 10 mL saline rinse gave a baseline temperature which lasted for 2.5 min. Conclusion: Neuro-endoscope causes higher thermal releasing in the surgical cavity of ESS, which should be especially cautious in the robotic system usage. Applying submaximal light intensity, a LED source and intermittent rinsing should be considered for the safer robot-assisted EES using a neuro-endoscope that allows a two-handed surgical procedure.

In Vivo Measurements of Middle Ear Temperature During Transcanal Endoscopic Ear Surgery

OBJECTIVE

The light emitted from the endoscope during transcanal endoscopic ear surgery (TEES) heats the intratympanic space. This heat may potentially be dangerous to nearby important structures, as documented by in vitro and by animal and cadaveric studies. The aim of our work was to monitor middle ear temperatures during TEES in vivo.

STUDY DESIGN

Cohort study.

SETTING

Tertiary referral hospital.

PATIENTS

Four patients (15-69 yrs old) underwent transcanal endoscopic tympanoplasties for chronic perforation or retraction.

INTERVENTION

After elevating the tympanomeatal flap, a thermocouple was placed in the middle ear to measure the heat generated by a 30° Hopkins rod telescope (11 cm long, 2.7 mm wide) and fiberoptic light emitting diode light source.

MAIN OUTCOME MEASURES

Middle ear temperature in the retrotympanum was monitored under these conditions: at 50 and 100% light intensity, after removing and wiping the endoscope tip, during suctioning and following middle ear irrigation.

RESULTS

Maximum middle ear temperature ranged from 36.26-37.30°C. Pulling out and wiping the endoscope caused no change or minimal decrease of 0.16°C. Middle ear irrigation caused a temperature drop of 2.05°C to 5.11°C. Suctioning was associated with a drop from 0.24°C to 3.91°C that was dependent on the depth of the endoscopic tip.

CONCLUSION

Middle ear temperatures during TEES using a Hopkins rod telescope and light-emitting diode light source reach values corresponding to physiological body temperature, and do not reach dangerous levels.

The application of a 70° endoscope in performing transcanal middle ear surgery

BACKGROUND

Endoscopes increase the expediency of transcanal middle ear surgery. However, the application of a 70° endoscope is limited and seldom discussed, mainly because of its large angle. We introduce our experiences with the 70° endoscope in transcanal middle ear surgery.

METHODS

This is a retrospective chart review of 127 patients with chronic otitis media who underwent middle ear surgery performed by the senior author in 2016 at a tertiary referral center. The types of eardrum perforation were classified as central, inferior, posterior, or anterior according to the main location of the hole. The demographics, surgical pictures, and operative records were reviewed.

RESULTS

In 15 ears of the 127 patients, the ossicles were recognized directly by a microscope. In another 112 ears, the ossicles could not be identified under a microscope. Without elevating the tympanomeatal flap, the ossicles could be recognized in 72 of these 112 ears with endoscopes, especially the 70° endoscope. In 35 of these 112 ears, an incision to extend the drum perforation or creation of a small tympanomeatal flap in the posterior-superior canal was made to observe the ossicles. However, 5 of these 112 ears were still noted to have a narrow and/or curved ear canal and preoperatively needed to undergo endaural incisions. Among the other 122 patients who first underwent attempted transcanal surgery, 15 ears changed to endaural incisions. The drum perforations were repaired directly through the perforation in 107 ears via the transcanal route. One year after surgery, the air-bone gap closure was 16.0 ± 11.8 dB, and the graft take rate was 91.3%.

CONCLUSION

With the help of a 70° endoscope, we can use the transcanal transperforation route to evaluate and reconstruct drum perforations and ossicular chains in appropriate patients. Hence, normal tissue injuries to the ear canal can be minimized.

Reducing fire and burn risk in the operating room-testing of a novel device

BACKGROUND

Burn injury and operating room fires are significant risks for both surgical patients and staff. The purpose of this study was to examine the fire and burn risks associated with two types of fiberoptic light cables and evaluate the efficacy of a novel device in reducing the risk of these fire and burn injuries.

METHODS

A 300-W light source was connected sequentially to two standard fiberoptic cables (Storz and Olympus). The distal ends were buried in, or rested on, standard operating room materials including a cotton green towel and a blue propylene drape to assess the risk of fire formation or burn injury. The Gloshield device was then attached to the ends of the cables and the experiment was repeated. Trials simulating improper use of the device were then conducted with the Gloshield device placed either too deep or too shallow on the end of the light cable. All trials were conducted for a maximum of 10 min or until a positive result (burn or fire) was achieved. Trials were conducted in room air or with supplemental 100% oxygen and repeated for accuracy.

RESULTS

Both the Storz and Olympus fiber optic cables were capable of producing burns in standard operating room towels and drapes in control trials. The Gloshield device prevented thermal injury when properly attached in all conditions. Improper use trials demonstrated that the device may be ineffective when not applied properly.

CONCLUSIONS

The Gloshield device is effective in reducing the risk of thermal burn injury by protecting the distal ends of endoscopic light cables from operating room materials. However, the device needs to be attached appropriately in order to provide protective benefits.

Future of Endoscopic Ear Surgery

Endoscopic ear surgery has gained popularity in recent years, becoming standard practice in otology centers around the world as an adjunct to conventional microscopic surgery and as a sole tool for limited disease. During the last years, technical improvements and growing expertise in the handling of the endoscope allowed introducing an exclusive endoscopic approach to the middle ear, lateral skull base, middle cranial fossa, and posterior fossa/cerebellopontine angle pathologies. Endoscopic instrumentation, techniques, and knowledge have improved during the last few years, and in the future, endoscopic surgical techniques will gain even more importance in otologic surgery.

Endoscopic Stapes Surgery: Pearls and Pitfalls

The endoscopic approach to stapes surgery affords unique advantages but is not without its specific challenges. The following reviews the equipment and surgical steps required to perform endoscopic stapes surgery safely and effectively, highlighting tips and potential points of failure through a series of case examples.

Prolonged intra-operative thermal exposure in endoscopic ear surgery: is it really safe?

OBJECTIVE

The aim of this study was to assess change in temperature, audiometric outcomes and post-operative complications following exposure to different light sources during endoscopic ear surgery.

METHOD

A total of 64 patients diagnosed with chronic otitis media with central perforation and pure conductive hearing loss underwent endoscopic type 1 tympanoplasty. The patients were randomised into two groups based on the light source used: xenon or light-emitting diode. Temperature was measured using a K type thermocouple at the promontory and round window niche. Mean temperature change with respect to operating time, mean audiometric change, incidence of vomiting in the first 24 hours, vertigo and tinnitus at the end of the first week were observed.

RESULTS

Mean temperature change showed a statistically significant difference with increasing length of operating time with the xenon light source and when the two light sources were compared for a particular time interval. Mean audiometric change showed statistically significant deterioration at higher frequencies (4, 6 and 8 kHz) with the xenon light source but only at 8 kHz for the light emitting diode source. When the mean audiometric change was compared between light sources for a particular frequency, statistical significance was found at 4, 6 and 8 kHz. Post-operative complications were vomiting, vertigo and tinnitus (p-values of 0.042, 0.099 and 0.147, respectively, between two groups).

CONCLUSION

Light emitting diodes are associated with less significant middle-ear temperature rises and audiometric changes at higher frequencies when compared to xenon light sources. Hence, xenon should be replaced with cooler light sources.

Can endoscopic ear surgery replace microscopic surgery in the treatment of acquired cholesteatoma? A contemporary review

Acquired cholesteatoma leads to significant morbidities while current surgical options remain a challenge. The principles of surgery include complete removal of disease, prevention of recurrence, and restoration of hearing function when possible. Traditionally, this has been performed using microscopes; however, a novel technique using endoscopes offers a new perspective on our understanding of anatomy, pathogenesis and surgical approaches. In recent years, various studies have demonstrated good outcomes with transcanal endoscopic ear surgery (EES) in cholesteatoma surgery. Nevertheless, the use of EES is not universal and remains controversial due to the efficacy of microscopes, specific limitations of endoscopes and the need to learn new skills. This review focuses on recent advances in EES for the treatment of acquired cholesteatoma, benefits, current challenges, and a discussion on the indications and contraindications of EES.

Too Hot to Handle-Quantifying Temperature Variations in the Nasal Endoscope Ocular Assembly and Light Post

Background

Nasal endoscopes have transformed and improved the safety of intranasal and transnasal surgery. The heat they can produce may, however, reach dangerous levels for surgeons. Studies have not previously assessed the temperature of the nasal endoscope light post/ocular assembly (LP/OA)—where the surgeon usually holds the endoscope.

Objective

This study aims to understand the effect of different nasal endoscopes, light sources, and light cords on the LP/OA temperature.

Methods

We measured the temperature at the LP/OA of various rigid nasal endoscopes at multiple time intervals over 30 minutes, as well as after turning off the light source and irrigating the LP/OA with 10 mL of saline.

Results

The highest temperature recorded was 67.37°C at the LP/OA at 30 minutes, using a new light cord, older endoscope, and 184-hour xenon light bulb. In every trial, the temperature of the LP/OA continually increased until 30 minutes when the light source was turned off. Statistically significant ( P < .001) temperature differences were seen in trials using the older xenon light sources. The light-emitting diode light source was significantly cooler with an older light cord regardless of the age of the scope ( P = .003).

Conclusion

Endoscope temperatures during sinus surgery may reach potentially dangerous levels at the LP/OA region. These temperatures may be sufficient to cause second-degree burns during normal usage. Factors associated with higher endoscope temperatures include longer times with the light source on and xenon light bulbs.

Complications in Endoscopic Ear Surgery

OBJECTIVE

The aim of this study was to examine the premise that endoscopic ear surgery (EES) is associated with a low rate of complications (intraoperative and postoperative).

STUDY DESIGN

Retrospective review at two institutions.

SETTING

Tertiary referral center.

PATIENTS

The study included 825 patients who underwent exclusive EES between 2008 and 2016 at the Otorhinolaryngology-Head and Neck Surgery Department of Modena University Hospital, and between 2014 and 2016 at the Otorhinolaryngology-Head and Neck Surgery Department of Verona University Hospital.

INTERVENTIONS

Exclusive endoscopic ear surgery between 2008 and 2016 (tympanoplasties, second look or revision tympanoplasties, myringoplasties, stapedoplasties, canalplasties, ossiculoplasties, and exploratory tympanotomies). All surgical procedures were performed by two experienced surgeons.

MAIN OUTCOME MEASURE

For each procedure, intraoperative, and early and delayed postoperative complications were evaluated.

RESULTS

The most common ear pathologies for which patients were sent for EES were cholesteatoma (33.6%), chronic otitis media (36.3%) and otosclerosis (26.8%). There was no case of major intraoperative complications such as injury to the dura or vascular structures. We observed minor intraoperative complications in 4.1% of the cases. Only 1.3% of patients experienced early postoperative complications. Delayed complications affected less than 1% of the cohort.

CONCLUSIONS

Data from this study confirm the safety of the endoscopic technique, with very low complication rates, indicating that EES is a reliable therapeutic option, in particular, for tympanoplasties, myringoplasties, and stapedoplasties, as well as second look procedures. We have reported our experience with EES morbidity so that it can be compared with data from other centers using the same surgical technique.

The first Malaysian experience on totally endoscopic ear surgery

Introduction:

Totally endoscopic ear surgery (TEES) is defined as exclusive application of endoscope transcanally in otologic surgery. This study is aimed to highlight indications and ear pathologies for TEES. In addition, intraoperative, early postoperative and delayed postoperative complications of TEES will be also described in this study.

Methodology:

This is a retrospective study of TEES performed by a single experienced and trained otologist in endoscopic ear surgery in a single institution between 1 July 2014 and 31 June 2018. A total of 43 patients were recruited in this study. Sociodemographic information, indications for TEES, ear pathologies, type of surgery performed and complications of TEES were analyzed.

Results:

The indications for TEES comprised middle ear lesion (65.1%), followed by second look surgery (14.0%), external auditory canal lesion (11.6%) and internal acoustic meatus lesion and surgery for conductive hearing loss which were 4.7%. Various external auditory canal pathologies encountered for TEES were ear canal osteoma (4.7%), acquired ear canal stenosis (2.3%) and tumor (4.7%). Regarding middle ear pathologies, limited atticoantral cholesteatoma accounted for most of the cases, 46.5%. Other middle ear lesions included adhesive otitis media (14.0%), recurrent cholesteatoma (14.0%), tumor (4.7%), otosclerosis (2.3%) and ossicular discontinuity (2.3%). Internal acoustic meatus lesion constituted 4.7% of cases. Some 4.7% of cases developed intraoperative complications, while early and delayed complications were 7.0%.

Conclusion:

TEES is a feasible surgical technique for diverse ear pathologies in the otologic specialty. It is also proven to be safe with good surgical outcomes.

Evaluation of Ototoxicity of an Antifog Agent and the Suspected Underlying Mechanisms: An Animal Study

Use of rigid endoscopes has become widespread in middle ear surgeries, thereby attracting attention to the safety of antifog agents. However, few studies on the ototoxicity of antifog agents have been conducted. The purpose of this study was to evaluate hair cell damage and the underlying mechanisms caused by antifog agents using zebrafish larvae. We exposed zebrafish larvae at 3 days postfertilization to various concentrations of the antifog agent, Ultrastop (0.01, 0.02, 0.04, and 0.08%) for 72 hours. The average number of hair cells within 4 neuromasts of larvae, including supraorbital (SO1 and SO2), otic (O1), and occipital (OC1), in the control group were compared to those in the exposure groups. Significant hair cell loss was observed in the experimental groups compared to that in the control group (P < .01; control: 53.88 ± 4.85, 0.01%: 45.08 ± 11.70, 0.02%: 41.36 ± 12.00, 0.04%: 35.36 ± 16.18, and 0.08%: 15.60 ± 7.53 cells). Concentration-dependent increase in hair cell apoptosis by terminal deoxynucleotidyltransferase (TDT)-mediated dUTP-biotin nick end labeling assay (control: 0.00 ± 0.00, 0.01%: 3.48 ± 2.18, 0.02%: 9.64 ± 5.75, 0.04%: 17.72 ± 6.26, and 0.08%: 14.60 ± 8.18 cells) and decrease in the viability of hair cell mitochondria by 2-(4-[dimethylamino] styryl)-N-ethylpyridinium iodide assay (control: 9.61 ± 1.47, 0.01%: 8.28 ± 2.22, 0.02%: 8.45 ± 2.72, 0.04%: 7.25 ± 2.44, and 0.08%: 6.77 ± 3.26 percentage of total area) were observed. Antifog agent exposure can cause hair cell damage in zebrafish larvae, possibly by induction of mitochondrial damage with subsequent apoptosis of hair cells.

Comparison of endoscopic and microscopic ear surgery in pediatric patients: A meta-analysis

OBJECTIVES

Recently, the endoscope has been increasingly introduced for middle-ear surgery. To evaluate the postoperative outcomes of endoscopic ear surgery (EES) in pediatric patients, we did a qualitative analysis with a systematic review and quantitative analysis with meta-analysis of available literature.

METHODS

Studies reporting the comparative surgical outcomes of EES in pediatric patients were systematically reviewed by searching the MEDLINE, PubMed, and Embase databases from database inception through 2017. The selected articles included clinical studies conducted with at least 30 subjects and at least one postoperative parameter, including residual or recurrent cholesteatoma and graft success in tympanoplasty. Two investigators independently reviewed all studies and extracted the data using a standardized form. A meta-analysis was performed using a random-effects model and qualitative review was performed on the smaller studies.

RESULTS

Ten studies were identified as appropriate for quantitative meta-analysis and 19 studies for qualitative analysis. In the meta-analysis, residual or recurrence rate of cholesteatoma was significantly lower in the EES group than in the microscopic ear surgery (MES) group (odds ratio [OR]: 0.56, 95% confidence interval [CI]: 0.38-0.84, P = .005). The graft success rate of tympanoplasty was not statistically different between EES and MES groups (OR: 0.72, 95% CI: 0.41-1.26, P = .249). In the qualitative analysis, most of the studies reported similar audiological outcomes after tympanoplasty and success rate of cholesteatoma removal between the two groups.

CONCLUSIONS

It appears that EES reduces the risk of residual cholesteatoma in children and that the success of perforation closure is equivalent to MES. Laryngoscope, 129:1444-1452, 2019.

Intraoperative thermal safety of endoscopic ear surgery utilizing a holder

PURPOSE

Despite the ever-growing popularity of endoscopic ear surgery (EES), there are still concerns regarding the potential thermal risk associated with the use of light sources and also questions raised about the thermal safety of extended stationary applications of endoscopes with holders that allow the use of both hands in the middle ear. The temperature changes witnessed during EES when using different calipers on static endoscopes fitted with camera holders during true operations were measured, and effects of varying light source intensities, as well as the cooling effect of irrigation and suction, were investigated.

METHODS

This study included 12 patients with chronic otitis who were scheduled to undergo myringoplasty surgery. Two of five different endoscopes with xenon light sources (4 mm-0°, 3 mm-0°, 2.7 mm-0°, 3 mm-45° and, 2.7 mm-30°) were used on each patient. Following irrigation and aspiration, gradually increasing heat measurements were recorded at two-minute intervals using a thermocouple thermometer for the entire period the endoscope remained in the ear. Three measurements obtained within the final 6 min, all of which were the same and reached a plateau, were considered to be the peak heat value. Measurements were repeated twice in each patient at 100% and 50% light intensities.

RESULTS

The highest heat was recorded by the 4 mm-0° endoscope, with heats at 100% and 50% light intensity recorded as 48.4 °C and 43.2 °C, respectively. The highest heat was measured by the 2.7 mm-0° endoscope, and heats recorded at 100% and 50% light intensities were 37.8 °C and 35.3 °C, respectively.

CONCLUSION

Stationary use of endoscopes with 3 mm and smaller calipers without irrigation or aspiration, the heat in the middle ear would appear to be safe, and at a level that does not cause thermal trauma to tissue. The present study demonstrates that frequent aspiration or intermittent irrigation may prevent potential thermal damage, even in procedures performed using endoscopes of a 4 mm caliper. Light intensity settings of 50% can be adopted as a further safety measure against potential thermal risk without compromising visual acuity.

Using a Video-Laparoscope for Intraoperative Colonoscopy: An Experimental Study on Intraluminal Temperature Values and Tissue Damage

Laparoscopy systems possess remarkable heat production. Video-laparoscopy was used for colonoscopy intraoperatively in rabbits. Rod lens type laparoscopes 5 and 10 mm in diameter connected with 175 and 300-W xenon light sources were used in combination. Physiological parameters including blood pressure, pulse, oxygen saturations, and luminal temperatures were investigated during 20 minutes of colonoscopy. Thermal damage scores were obtained by histopathologic analysis of the intestinal wall. The changes were categorized as physiological and structural. Damage scores were not different when 175-W light source was used with 5- and 10-mm laparoscopes. Intraluminal heat values most increased with 300 W plus 10-mm laparoscope and caused significant increase in damage scores. Structural damage indicating tissue necrosis was not observed with any of the combination in all groups. Video-laparoscopy systems did not cause significant tissue damage when used at low and moderate levels of xenon light source in the rabbit bowel intraoperatively.